Questions on optimizing Mathematica code for higher performance. This may mean faster execution, lower memory usage or both. Not to be confused with mathematical optimization.

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2
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1answer
123 views

How can I reduce computation time while still obtaining a good approximation for my function?

I am new to any CAS (and Mathematica, for that matter) and new to StackExchange too, so forgive me and correct me on any mistakes. I have this function: $J_p=\sum_{m,n=1}^{\infty} ...
21
votes
2answers
455 views

Why is Query so much slower than Part?

Time for another of these(1),(2) as yet another new-in-10 function appears to have poor performance compared to older alternatives. This time: Query appears to be ...
1
vote
1answer
241 views

Performance of compiled functions (Project Euler No14)

I was playing around with the project euler problem 14. The solution I came up with is listed below as cf1. The solution works fine but I get the compiler warning: ...
1
vote
0answers
151 views

Speeding Up Image Processing Functions

I am working with stacks of 1024x1024 timelapse microscopy images that I am performing a series of image processing functions on to help segment each image. These functions include ...
15
votes
1answer
316 views

Speed up adding Poisson noise to an image

I'm simulating some images corrupted with Poisson noise, but I'm encountering a few problems with performance. According to the documentation on ImageEffect, one ...
5
votes
1answer
152 views

Is there a faster way to Map an Association?

Consider mapping an existing Association in a manner such as this: ...
0
votes
0answers
121 views

Improving the speed of evaluating Table with nested functions

I am a Mathematica novice working with a stack of 1024 x 1024 WatershedComponents (or MorphologicalComponents) label matrices ...
8
votes
4answers
320 views

Fast method to select matrix elements based on a vector of positions

There is an operation for which I have long wanted to find a better solution. Let: a be a matrix of dimensions $m\times n$ ...
1
vote
1answer
64 views

A code deal with Lists operation ---Needs optimizion

I have written some code to deal with lists, But the speed of the code is slow, Could Someone help me to speed up it? Probably could rewrite it with Functional Programming! Give me some ideas! The ...
0
votes
0answers
79 views

strange timing behavior

The following code is from a book about Mathematica. ...
2
votes
3answers
126 views

Speeding Up Replacing of Labels in Large Matrix?

I am Mathematica novice and am trying to find a fast way to replace labels in some rather large matrices (512x512 or 1024x1024) that have resulted from segmenting images with WatershedComponents or ...
1
vote
0answers
120 views

Speeding up NDSolve for system of differential equations

I am wondering if there is a way to speed up this function that solves a system of ordinary differential equations with NDSolve? Thus far I've tried specifying a few different methods such as LSODA, ...
0
votes
1answer
37 views

Timing enclosed by Manipulate not working [closed]

Manipulate[Timing[Show[somegraphs[[1 ;; i]]]], {i, 1, 500, 1}] (in Mathematica 8) This is the last line of my function f[x_]:= Module[....]. I am trying to combine a list of graphs into a single ...
7
votes
1answer
62 views

Issuing user-defined messages takes a long time (Message is slow)

Issuing messages takes a very long time in version 9 and version 10. Can others reproduce this? Is there a fix? Update: This is slow only when using the front end, but not when running the kernel ...
1
vote
1answer
67 views

Warning and Errors during Compile

I defined a compiled function cf = Compile[{{x, _Integer}, {n, _Integer}}, z = (n^x); Binomial[n, #]* StirlingS2[x, #] *(#!)/z & /@ Range[x]]; and I ...
2
votes
3answers
77 views

Reduction of repetitive calculations in Table

If I generate two tables inside a function which are function[n_, x_, y_]:=( table1 = Table[i* x/n^x, {i,1,n}]; table2 = Table[i* y/n^y, {i,1,n}]; ) where ...
6
votes
1answer
173 views

Optimizing the front end on the Raspberry Pi

Using Mathematica's Front End on the Raspberry Pi is truly a test of one's patience. The most basic of notebooks become unresponsive after seemingly trivial additions to the notebook. Consider the ...
24
votes
1answer
764 views

Mma 10: Half the parallel power (Macs)?

Here is a comparison of the parallel kernels launched under Mathematica under v9 and v10, on the same identical current 2014 R2-D2 Mac Pro ... [ Update: Valerio has commented that the same issue ...
0
votes
0answers
93 views

Timing: how make a program to work faster using built in functions and tables

I want to improve my code to make it working faster even for very large numbers. ...
12
votes
1answer
301 views

the more effective method to find 21 digits armstrong number

In recreational number theory, a narcissistic number (also known as a pluperfect digital invariant (PPDI), an Armstrong number(after Michael F. Armstrong) or a plus perfect number) is a number that is ...
0
votes
0answers
94 views

Complex Convolution

I am attempting to integrate a convolution variable using the following code. However, the program is taking too long to complete the integration. Does anybody have any coding tips that may make ...
2
votes
2answers
183 views

Alternative for MapThread in listable functions

How can I rewrite this more efficiently taking advantage of flo, dem, and Nsup being ...
7
votes
4answers
232 views

Position of Subsets in a List

I have a particular list of integers and a matrix whose entries are lists. Say I know that my particular list is a subset of at least some of the elements in the matrix. I want to find an efficient ...
1
vote
0answers
89 views

Speeding up the numerical integration of a certain function

I'm using the following function f[t_] := 3/4 t^-3 NIntegrate[(x^4*Csch[x/2]^2), {x, 0, t}, Method -> {Automatic, "SymbolicProcessing" -> 0}]; I ...
5
votes
1answer
225 views

More efficient Omnibus number determination?

Amusing myself with concepts from "Omnibus Sequences, Coupon Collection, and Missing Word Counts", in particular the sequences. To paraphrase the concept, a string is k-Omni over some alphabet a if ...
0
votes
0answers
72 views

Timing Differences

In More efficient implementation for comparing coefficient lists in a Do-loop link, george2079 posts in his first answer a piece of code that takes 352 seconds to compute. When I run this same piece ...
1
vote
0answers
91 views
24
votes
3answers
863 views

Smooth Peter de Jong attractor

Today I was playing with Peter de Jong attractor. At the bottom of the page I've linked there are beautiful examples like: My attempts are not so great: It is around 10^5 points. For more than ...
2
votes
3answers
273 views

Alternative ways to AppendTo and Delete in a While loop

Is there an alternative way to do AppendTo and Delete and also replace k0 during every ...
0
votes
0answers
54 views

Expectation taking unusually long to evaluate

I am trying to evaluate an expectation, but it is taking an extremely long time although the expression itself should not be too complicated. My code is ...
10
votes
5answers
439 views

How would you efficiently implement BinListsBy?

Let's say I have a list like this: data = {{21, "Alice"}, {27, "Bob"}, {22, "Charles"}, {34, "Dora"}, {75, "Eliza"}} containing ages and names of persons. What I ...
0
votes
1answer
94 views

Help with Computation-heavy triple integration

I'm Trying to use Mathematica to symbolically integrate a function with respect to x, y, and z. For some reason, this computation either takes about, 60s and returns the input, or takes many hours ...
3
votes
0answers
171 views

Understanding performance: graph connected components

I need to analyze directed graphs with 10M edges, 1M vertices, and 300K strongly connected components, so that the largest one contains 400K vertices. I read some explanations of Leonid Shifrin here, ...
7
votes
4answers
522 views

Generating an Ulam spiral

An Ulam Spiral is quite an interesting construction, revealing unexpected features in the distribution of primes. Here is a related topic with one answer by Pinguin Dirk, who has provided one ...
10
votes
1answer
332 views

Poor performance from Graphics3D

I wrote a game -- 2048,Some codes are from http://blog.wolfram.com/. My codes are in notebook downloads I added code so that the game can play in 3D form, but when I play it, I find that it is too ...
1
vote
0answers
41 views

A more efficient way of fitting a non-linear model that returns an entire list?

I have a function that takes two parameters, del and nu, and returns a list npoints long ...
8
votes
2answers
314 views

Finding all sets of elements with two common elements in a large dataset

I have a very large network of atoms ($\approx 10^6$ atoms) with fixed positions that resemble a cellular structure: I have two files including: fixed locations of each atom set of points which ...
5
votes
2answers
107 views

ReplaceAll performance problem: packed arrays on the LHS are unpacked when the RHS is too long

The following is one of the most mysterious performance problems I encountered and came up while extending the booleval function mentioned here. I am looking for a ...
3
votes
1answer
80 views

Usage of Block in Compile

When is there an advantage to using Block in Compile? For instance, if I have a multiple-step code, how do I decide which ...
7
votes
3answers
389 views

Speed up ContourPlot3D

I have two issues with the following code. (1) It executes too slowly. If I use "Speed" instead of "Quality" for PerformanceGoal, I get the speed but an undesirable delay in proper rendering of the ...
1
vote
0answers
120 views

Are there any plans to develop Wolfram OS? [closed]

Are there any plans to develop Wolfram OS? Google has developed Chrome OS/Chromium OS dedicated to easy and fast access to the web. Valve has developed Steam OS that created primarily for playing ...
1
vote
0answers
113 views

How to tweak the following purely numerical code

I am using the following numerical function in my program and I would like to speed it up. ...
18
votes
1answer
1k views

Faster way to compute the distance from a point to a surface in 3D

I am trying to compute the shortest distance between a point and a triangle in 3D ...
19
votes
1answer
2k views

Why won't Parallelize speed up my code?

What reasons are there that can cause parallelized Mathematica code not to run with full performance?
2
votes
1answer
104 views

Randomly generated polymer with certain spatial density

For simplicity's sake, let the polymer's composing particle be integer 3-tuples (on 3D Cartesian grid), such that: Polymer-ness -- for all particle there is an directly adjacent neighbor. i.e in ...
1
vote
0answers
38 views

can I evaluate multiple cells at the same time? [duplicate]

my laptop has 2 cores, can I assign a core to evaluate one code, and the other core for another code in parallel instead of evaluating in sequence? thanks
7
votes
1answer
224 views

Why do Tooltips slow down Dynamic so much? Is there a faster alternative?

I'm working on a Dynamic ListPlot with a few thousand plots, and it seems that wrapping the points with Tooltip slows the Dynamic responsiveness substantially. With the simple example below, dragging ...
0
votes
1answer
128 views

Plot a solid generated by a family of surfaces

I'm trying to graph a series of planes as a solid object in Mathematica. I first tried to use the Plot3D options as well as the fill options to plot a $3D$ volume, ...
1
vote
2answers
218 views

A fast way to compare interval

I have a list of intervall. Some of these intervals are disjoint, some are overlapped and some are included in others. To leave no ambiguity about my explanation, you can see the following examples: ...
1
vote
0answers
43 views

Hashing by Equals instead of SameQ

I have some numerical code involving complex numbers representing points on a plane. Some of these are equal but not identical, ie ...